Locating the Agropyron segment in wheat–Agropyron transfer no. 12

Genome ◽  
1987 ◽  
Vol 29 (2) ◽  
pp. 365-366 ◽  
Author(s):  
G. C. Eizenga

Twelve lines of wheat (Triticum aestivum L.) were originally identified as having a segment of Agropyron elongatum chromatin carrying a gene for resistance to leaf rust (Puccinia recondita tritici) transferred to wheat chromosome 7D. By studying the chromosome pairing of one of these lines, transfer no. 12, with telosomes 7AL, 7AS, 7BL, 7BS, 7DL, 7DS, and 7AgS, it was determined that the Agropyron chromatin was carried on the long arm of wheat chromosome 7A rather than 7D. This determination was confirmed by acetocarmine–N-banding. Key words: Triticum aestivum, Agropyron elongatum, transfer lines, Puccinia recondita tritici, telosomic analysis.

1984 ◽  
Vol 26 (6) ◽  
pp. 736-742 ◽  
Author(s):  
R. P. Singh ◽  
R. A. McIntosh

Two complementary genes, A and B, conferring resistance to Puccinia recondita tritici in various wheats were located in chromosomes 4Aβ and 3BS, respectively. In one study gene B showed recombination of 33.6 ± 4.1% with the centromere, and was independent in a second study. Gene B was the same as that designated Lr27. A new designation, Lr31, is proposed for gene A. Both Lr27 and Lr31 must be present for the expression of resistance.Key words: leaf rust, monosomic analysis, aneuploids, wheat.


1977 ◽  
Vol 19 (4) ◽  
pp. 711-716 ◽  
Author(s):  
P. L. Dyck

The genetics of seedling resistance to leaf rust (Puccinia recondita Rob. ex. Desm.) was investigated in what (Triticum aestivum L.) introductions PI 268454, PI 58548 and PI 268316, originally collected in Afghanistan, China and Iran, respectively. PI 268454 was heterogeneous for resistance. A selection (PI 268454a) has a gene that confers a 1+ reaction while a second selection (PI 268454b) probably has resistance gene Lr2b. PI 58548 has two genes for resistance, one giving a 1+ reaction and the second a 2+. These two genes interact to produce a; 1 reaction. PI 268316 has three interacting genes, one giving a 1+ reaction, the second a 2+ and a third resistance gene similar to LrB. The gene giving the 1+ reaction was common to all three introductions. PI 58548 and PI 268316 carry different genes for infection type 2+. Backcross lines of the single genes were produced. Implications to breeding for disease resistance of genes interacting to produce different phenotype are discussed.


Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 463-466 ◽  
Author(s):  
P. L. Dyck ◽  
E. R. Kerber ◽  
O. M. Lukow

A gene for resistance to Puccinia recondita, originally detected in wheat (Triticum aestivum L.) accessions PI58548, PI268454, and PI268316, has been located on the long arm of chromosome 1B, 3.1 ± 1.2 crossover units from the centromere. In a cross between the backcross line RL6057 containing this new gene, now designated Lr33, and the backcross line RL6078 containing gene Lr26, gene Lr33 is closely linked to gene Lr26 (or the translocation breakpoint) with an estimated 2.6 ± 0.8 recombination value. RL6057 and RL6078 differ in gliadin bands that are controlled by genes on the short arm of chromosome 1B or 1R. The banding difference was completely associated with the presence or absence of Lr26. Key words: Triticum, Puccinia, linkage.


1977 ◽  
Vol 19 (2) ◽  
pp. 355-358 ◽  
Author(s):  
P. L. Dyck ◽  
E. R. Kerber

The inheritance of seedling resistance to leaf rust (Puccinia recondita) was studied in wheat (Triticum aestivum L.) cultivars Rafaela and EAP 26127. Rafaela has genes Lr14b and Lr17 while EAP 26127 has Lr17. Lr17 was located on chromosome 2A, possibly the short arm, and was independent of Lr11.


1976 ◽  
Vol 18 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Jan Dvořák

Chromosome pairing was studied in a number of hybrids involving a 56-chromosome wheat-Agropyron derivative, PW 327. PW 327 originated from the cross, Triticum aestivum cv. Chinese Spring (Chinese Spring × A. elongatum, 2n = 70). In hybrids between PW 327 and T. aestivum a number of multivalent chromosome associations were formed at metaphase I. These multivalents result from interchanges which occurred among wheat chromosomes 1A, 1D, 2A, 2D, 4D and 6D of PW 327. One chromosome of the Agropyron chromosome set of PW 327 occasionally pairs with wheat chromosome 3B. The rest of the Agropyron chromosomes present in PW 327 do not pair with the chromosomes of T. aestivum. It is proposed that the set of Agropyron chromosomes present in PW 327 is not an intact genome of decaploid A. elongatum but rather a modified synthetic genome combining chromosomes and/or chromosome segments from different genomes of the Agropyron parent. The incorporation of duplication-deletions into synthetic genomes of natural polyploids is discussed and it is shown that the set of Agropyron chromosomes which is present in PW 327 carries at least one such duplication-deletion. Pairing between chromosomes of diploid and decaploid A. elongatum was studied in a 56-chromosome hybrid from a cross between an amphiploid, T. aestivum × A. elongatum (2n = 14), and PW 327. It appeared that at least four chromosomes of these two Agropyrons occasionally paired with each other in this hybrid in which the diploidizing system of wheat was active. The relationship between chromosomes of diploid and decaploid A. elongatum is discussed.


1979 ◽  
Vol 21 (2) ◽  
pp. 243-254 ◽  
Author(s):  
J. Dvořák

Ten telocentric chromosomes of diploid Agropyron elongatum (Host.) P.B. (2n = 14) were added to the chromosome complement of Triticum aestivum L. emend. Thell. The ditelosomic additions were crossed with Triticum speltoides (Tausch) Gren. ex Richter, and in the tetraploid hybrids the pairing frequencies of the telosomes were determined, expressed as percent of PMC's in which a telosome paired at metaphase I. All Agropyron telosomes paired with Triticum chromosomes. The pairing frequencies ranged from 4.4% to 41.2% of the PMC's, it is concluded that none of the ten Agropyron chromosome arms has a homologous partner among the four Triticum genomes involved. The pairing frequencies did not correlate with the lengths of the telosomes. Pairing of the Agropyron telosomes in these tetraploid hybrids approximated the chromosome pairing that occurred in a diploid hybrid T. tauschii (Coss.) Schmal. (the donor of the D genome of T. aestivum) × A. elongatum.


1980 ◽  
Vol 22 (2) ◽  
pp. 237-259 ◽  
Author(s):  
J. Dvořák

Genetic compensation of Agropyron chromosomes for wheat chromosomes in the male gametophyte and compensation of Agropyron chromosomes for wheat chromosomes in disomic substitutions were used to investigate relationships between the chromosomes of Agropyron elongatum (Host.) P.B. (2n = 2x = 14) and Triticum aestivum L. emend. Thell. (2n = 6x = 42). Gametophytic compensation indicated that A. elongatum chromosomes I, II, III, IV, and VII were related to wheat chromosomes of homoeologous groups 1, 7, 4, 3, and 6, respectively, and were designated 1E, 7E, 4E, 3E, and 6E. Chromosomes V and VI appeared to be related to homoeologous group 2. Other analyses showed that chromosomes V and VI originated from arm exchanges between chromosome 2E and other Agropyron chromosomes. An unaltered disome of Agropyron chromosome 2E was added to the wheat chromosome complement. In the disomic substitutions Agropyron chromosomes 1E, 6E, and 7E compensated for all three wheat homoeologues of the respective homoeologous groups. Chromosome 4E fully compensated for chromosome 4D but only partially for chromosomes 4A and 4B. Chromosomes V and VI compensated poorly or not at all for wheat chromosomes of group 2.


1981 ◽  
Vol 23 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Y. Yasumuro ◽  
R. Morris ◽  
D. C. Sharma ◽  
J. W. Schmidt

A study was initiated to transfer genes for stem- and leaf-rust resistance from a chromosome (designated 6Ag) of Agropyron elongatum (Host) Beauv to a homoeologous chromosome (6D) of wheat (Triticum aestivum L. aestivum group) by inducing pairing between 6Ag and 6D in the absence of the Ph gene on wheat chromosome 5B. Plants monosomic for SB, 6D and 6Ag were crossed with Chinese Spring nullisomic-5B tetrasomic-5D or with Chinese Spring monosomic or trisomic for SB with an induced mutation, phlb, of the Ph locus. Tests of 282 offspring in the seedling stage for reaction to the stem rust pathogen, Puccinia graminis Pers. f. sp. tritici Eriks. &E. Henn. race 56 or 15B-2, were used to identify 70 plants with 6Ag, which was transmitted through 25% of the female gametes. Meiotic observations on 51 of these plants indicated that six were monosomic for 6D and 6Ag, but lacked an entire 5B or had 5B with the phlb mutation. The frequency of metaphase I cells with pairing between 6D and 6Ag averaged 4.94% in three plants that were nullisomic for 5B and 2.48% in two plants that had a single dose of 5B with the phlb mutation.


Genome ◽  
1990 ◽  
Vol 33 (6) ◽  
pp. 892-897 ◽  
Author(s):  
J. Dvořák ◽  
D. R. Knott

A leaf rust resistant line, 2-9-2, was selected in the fourth backcross generation to Triticum aestivum of an interspecific hybrid, T. aestivum × Triticum speltoides. The resistance segregated independently of T. speltoides leaf rust resistance gene Lr28, previously shown to be incorporated into wheat chromosome 1B in two other transfer lines. Monosomic and telosomic analyses showed that the gene in line 2-9-2, Lr36, was incorporated into the short arm of chromosome 6B. C-banding analysis showed that the homoeologous crossing-over occurred distally to an interstitial C-band in the satellite and linkage analysis showed Lr36 to be tightly linked to the telomeric C-band.Key words: C-banding, physical mapping, linkage, wheat, chromosome 6B, introgression.


1992 ◽  
Vol 72 (1) ◽  
pp. 229-233 ◽  
Author(s):  
K. G. Briggs ◽  
K. Kutschera ◽  
S. Kibite

Cutler spring wheat (Triticum aestivum L.) is a very early maturing, semidwarf, spring wheat with special adaptation to the Parkland region of the Western Prairies, and is suitable for production where early maturity is a prime consideration and where leaf rust rarely occurs. It received registration No. 3356 and is eligible for grades of Canada Prairie Spring (red).Key words: Triticum aestivum L., spring wheat, early maturity, cultivar description


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